L Carnitine Injection: Maximize Fat Burning, Energy & Metabolism Injectable vs Oral L Carnitine: Which Works Better? AWP Injectable VS Liquid L Carnitine. Which is better? Injectable vs Oral L Carnitine: Which Works Better? AWP ORAL VS. INJECTABLE L CARNITINE , Does it really matter which you use? , Both have pros and cons but it really comes down to what is going to be most suited to use as an individual athlete.,